A full Cancer Center-managed facility, the Radiation Research Shared Resource is located within and maintained by the Center for Radiological Research. The facility provides a comprehensive irradiation service for members of the HICCC primarily and others. The primary services provided are: ? X-ray irradiation of cells and animal models ? Gamma-ray irradiation of cells and animal models ? UV irradiation of cells and animal models ? Training of users in experimental design and safe operation of the irradiators Demand for the facility has steadily increased during the last six years, where the number of independent user laboratories increased by 230% since 2000 (64 versus 28). The Radiation Shared Resource has machinery capable of exposing samples to x-rays, gamma-rays and ultraviolet light. Samples ranging from small macromolecules such as DMA and proteins, to microorganisms, mammalian cells in culture or small animals can be exposed. Research goals include such tasks as creating double strand breaks or bulky lesions in DMA, irradiating mice before injection of cells to test tumorigenicity, creating transformed cells, preparing feeder layers for tissue culture, , and measuring radiosensitivity of yeast, mouse, hamster or human cells. The facility has four irradiators, a Siemans X-ray Therapy Unit, an Atomic Energy of Canada Gammacell 40 Cesium Unit, a high-dose-rate Gammacell 220 Cobalt Unit, and a UV light box emitting 254 nm light. The operators of the facility provide users with guidance for safe and efficient sample exposure, as well as consultation on experimental design. The facility is operated in close association with the Radiation Safety Department to ensure compliance with governmental regulatory agencies. Future plans include the manufacture of an apparatus for subcellular stripe irradiation of cells in culture, another apparatus capable of rotating animals during x-ray exposure to permit irradiation of an internal anatomical target while limiting exposure to surrounding tissues, and working with the Institute for Comparative Medicine at CUMC to develop an imaging system for targeting radiation to anatomical sub-regions in mouse models of cancer. During the last period of the CCSG, 39% of the investigators using the facility were Cancer Center members with peer-reviewed funding with those members representing approximately 60% of the usage of the primary services. The proposed total operating budget of the facility is $110,022, of which we are requesting $ 61,612 from the CCSG.